At fixed temperature and `600 mm` pressure, the density of a gas is `42`. At the same temperature and `700 mm` pressure, what is the density of the gas?

Explanation

To solve the problem of finding the density of a gas at a different pressure while keeping the temperature constant, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Given Values:**
- Initial pressure (P1) = 600 mm
- Initial density (d1) = 42
- Final pressure (P2) = 700 mm
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